Nanedi Valles Valley System
This image shows the Nanedi Valles valley system, a steep-sided feature that may have been formed in part by free-flowing water. The HRSC obtained the image on 3 October 2004 during orbit 905 at a ground resolution of approximately 18 metres per pixel. The image has been rotated 90 degrees clockwise, so that north is to the right.
The scene shows the region of Nanedi Valles, a roughly 800-kilometre valley extending southwest-northeast and lying at approximately 6.0° North and 312° East in the region of Xanthe Terra, southwest of Chryse Planitia.
In this colour image, Nanedi Valles ranges from approximately 0.8- to 5.0-kilometre wide and extends to a maximum of about 500 metres below the surrounding plains. This valley is relatively flat-floored and steep-sloped, and exhibits meanders and a merging of two branches in the north.
The origin of these striking features remains heavily debated. Some researchers point to sapping (erosion caused by ground-water outflow), while others suggest that flow of liquid beneath an ice cover or collapse of the surface in association with liquid flow is responsible for the valley's formation. While the debate continues, it seems likely that some sort of continuous flow rather than a single flooding event created these features.
This colour image has been derived from the three HRSC colour channels and the nadir channel. Image resolution has been reduced for use on the internet.
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